Adding the wrongly removed module back in pom.xml

[controller.git] / opendaylight / md-sal / sal-akka-raft / src / main / java / org / opendaylight / controller / cluster / raft / behaviors / Leader.java

diff --git a/opendaylight/md-sal/sal-akka-raft/src/main/java/org/opendaylight/controller/cluster/raft/behaviors/Leader.java b/opendaylight/md-sal/sal-akka-raft/src/main/java/org/opendaylight/controller/cluster/raft/behaviors/Leader.java
index 857c87f0aca82daaf425fcdc064978c9debf6fb1..26beed2f7a69b5191407f230c839edd1e4178ade 100644 (file)
--- a/opendaylight/md-sal/sal-akka-raft/src/main/java/org/opendaylight/controller/cluster/raft/behaviors/Leader.java
+++ b/opendaylight/md-sal/sal-akka-raft/src/main/java/org/opendaylight/controller/cluster/raft/behaviors/Leader.java
@@ -27,6 +27,7 @@ import org.opendaylight.controller.cluster.raft.messages.AppendEntries;
 import org.opendaylight.controller.cluster.raft.messages.AppendEntriesReply;
 import org.opendaylight.controller.cluster.raft.messages.InstallSnapshot;
 import org.opendaylight.controller.cluster.raft.messages.InstallSnapshotReply;
+import org.opendaylight.controller.cluster.raft.messages.RaftRPC;
 import org.opendaylight.controller.cluster.raft.messages.RequestVoteReply;
 import scala.concurrent.duration.FiniteDuration;
 
@@ -118,20 +119,13 @@ public class Leader extends AbstractRaftActorBehavior {
     }
 
     @Override protected RaftState handleAppendEntries(ActorRef sender,
-        AppendEntries appendEntries, RaftState suggestedState) {
+        AppendEntries appendEntries) {
 
-        context.getLogger()
-            .error("An unexpected AppendEntries received in state " + state());
-
-        return suggestedState;
+        return state();
     }
 
     @Override protected RaftState handleAppendEntriesReply(ActorRef sender,
-        AppendEntriesReply appendEntriesReply, RaftState suggestedState) {
-
-        // Do not take any other action since a behavior change is coming
-        if (suggestedState != state())
-            return suggestedState;
+        AppendEntriesReply appendEntriesReply) {
 
         // Update the FollowerLogInformation
         String followerId = appendEntriesReply.getFollowerId();
@@ -143,6 +137,13 @@ public class Leader extends AbstractRaftActorBehavior {
             followerLogInformation
                 .setNextIndex(appendEntriesReply.getLogLastIndex() + 1);
         } else {
+
+            // TODO: When we find that the follower is out of sync with the
+            // Leader we simply decrement that followers next index by 1.
+            // Would it be possible to do better than this? The RAFT spec
+            // does not explicitly deal with it but may be something for us to
+            // think about
+
             followerLogInformation.decrNextIndex();
         }
 
@@ -177,7 +178,7 @@ public class Leader extends AbstractRaftActorBehavior {
             applyLogToStateMachine(context.getCommitIndex());
         }
 
-        return suggestedState;
+        return state();
     }
 
     protected ClientRequestTracker findClientRequestTracker(long logIndex) {
@@ -191,17 +192,30 @@ public class Leader extends AbstractRaftActorBehavior {
     }
 
     @Override protected RaftState handleRequestVoteReply(ActorRef sender,
-        RequestVoteReply requestVoteReply, RaftState suggestedState) {
-        return suggestedState;
+        RequestVoteReply requestVoteReply) {
+        return state();
     }
 
     @Override public RaftState state() {
         return RaftState.Leader;
     }
 
-    @Override public RaftState handleMessage(ActorRef sender, Object message) {
+    @Override public RaftState handleMessage(ActorRef sender, Object originalMessage) {
         Preconditions.checkNotNull(sender, "sender should not be null");
 
+        Object message = fromSerializableMessage(originalMessage);
+
+        if (message instanceof RaftRPC) {
+            RaftRPC rpc = (RaftRPC) message;
+            // If RPC request or response contains term T > currentTerm:
+            // set currentTerm = T, convert to follower (§5.1)
+            // This applies to all RPC messages and responses
+            if (rpc.getTerm() > context.getTermInformation().getCurrentTerm()) {
+                context.getTermInformation().updateAndPersist(rpc.getTerm(), null);
+                return RaftState.Follower;
+            }
+        }
+
         try {
             if (message instanceof SendHeartBeat) {
                 return sendHeartBeat();
@@ -210,7 +224,6 @@ public class Leader extends AbstractRaftActorBehavior {
             } else if (message instanceof Replicate) {
                 replicate((Replicate) message);
             } else if (message instanceof InstallSnapshotReply){
-                // FIXME : Should I be checking the term here too?
                 handleInstallSnapshotReply(
                     (InstallSnapshotReply) message);
             }
@@ -276,20 +289,28 @@ public class Leader extends AbstractRaftActorBehavior {
             List<ReplicatedLogEntry> entries = Collections.emptyList();
 
             if(context.getReplicatedLog().isPresent(nextIndex)){
+                // TODO: Instead of sending all entries from nextIndex
+                // only send a fixed number of entries to each follower
+                // This is to avoid the situation where there are a lot of
+                // entries to install for a fresh follower or to a follower
+                // that has fallen too far behind with the log but yet is not
+                // eligible to receive a snapshot
                 entries =
                     context.getReplicatedLog().getFrom(nextIndex);
             }
 
             followerActor.tell(
-                new AppendEntries(currentTerm(), context.getId(),
-                    prevLogIndex(nextIndex), prevLogTerm(nextIndex),
-                    entries, context.getCommitIndex()
-                ),
-                actor()
-            );
+                new AppendEntries(currentTerm(), context.getId(), prevLogIndex(nextIndex),
+                    prevLogTerm(nextIndex), entries, context.getCommitIndex()).toSerializable(),
+                actor());
         }
     }
 
+    /**
+     * An installSnapshot is scheduled at a interval that is a multiple of
+     * a HEARTBEAT_INTERVAL. This is to avoid the need to check for installing
+     * snapshots at every heartbeat.
+     */
     private void installSnapshotIfNeeded(){
         for (String followerId : followerToActor.keySet()) {
             ActorSelection followerActor =